The creation is about a separating device of the automatic document feeder, particularly for that kind which can maintain the initial paper separating function at the paper feeding speed higher than 15 ppm.
As the time changes, nowadays the electrical products like scanner, fax, photostat, printer and etc. appear to provide the convenience for our life. Due to slow feeding speed and one piece of paper each time, the above products have long waiting time when using. So the development of the automatic paper feeding device can provide the single page separation and paper feeding to largely improve the disadvantage of the above electrical products.
Please refer to FIG. 1A and FIG. 1B, which is the prior art of the automatic document feeder. A paper feeding roller 20 is located at one side of the paper case 12, combined with a transmission mechanism 11 and connected with a paper carrying roller 10. So the paper feeding roller 20 rotates toward the same direction with the paper carrying roller 10. The paper carrying roller 10 can be moved downward to a paper case 12 to contact a piece of paper 13 and upward from the paper case 12 to lose contact with that paper 13 and so the paper carrying roller 10 move downward to carry paper 13 inside paper case 12 moving along the rolling tangent direction 91 to the paper feeding roller 20 to finish the automatic paper feeding.
The prior art paper separation device of automatic document feeder covers the following two mechanism. Please refer to FIG. 2, below the paper feeder roller 20 is a down roller 30; the two rollers have adequate contact. Due to the down roller 30 stopping when feeding paper, the paper feeder roller 20 can only roll one piece of paper 13 to pass through the two rollers. Without paper feeding, the down roller 30 rotates with the paper feeder roller 20 so the friction is less and the life is longer. But the down roller needs the total set of forming rollers to provide the above function so the design cost is higher. While the friction slice has low cost and easy design to control, so it has been widely used in the normal paper separation device.
Please refer to FIG. 3A, below the paper feeder roller 20 is a down friction slice mechanism 40. This down friction slice mechanism 40 has a down friction slice 41 to contact adequately with the paper feeder roller 20 and a elastic mechanism 42 combined on the down friction slice bottom 43 to provide an elastic force perpendicular to the rolling tangent direction 92. Cause the friction coefficient between the material of the paper feeder roller 20 and the paper 13 is larger than that between the material of the down friction slice 41 and the paper 13 and the friction coefficient between the material of the down friction slice 41 and the paper 13 is larger than that between the paper 13 and the paper 13, the paper feeder roller 20 can only carry one paper 13 through the paper feeder roller 20 when paper feeder roller 20 carrying more than one piece of paper. The extra pieces of paper 13 are stopped at the down friction slice mechanism 40 due to friction. When paper feeding finishes, due to lager friction, the paper feeder roller 20 rolls the paper 13 stopped at the down friction slice mechanism 40 to feed paper separately.
Please refer to FIG. 3B, when the paper feeder roller 20 doesn""t carry paper, the paper feeder roller 20 rubs against the down friction slice 41 and thus generates an arc hollow wear 44 at the same position. When the arc hollow wear 44 is too deep, the paper jam will occur and finish the life of down friction slice 41. High speed paper feeding will accelerate the wear to shorten the life of the down friction slice 41 and thus can""t provide the satisfactory life to the consumers. So, usually the speed in this device is lower than 10 ppm to provide the satisfactory life to the consumers.
The above two paper separation devices of automatic document feeder have their disadvantages in design cost and life. So it is necessary to develop a better paper separation device of automatic document feeder.
The object of this invention is to provide a paper separation device of automatic document feeder that can decrease the design cost and elongate the life.
To reach this object, the paper separation device of automatic document feeder in this invention can be combined with a paper case loaded at least one piece of paper to provide the automatic paper separation and feeding. The paper separation device of automatic document feeder includes: a paper feeder roller, a friction slice, a first elastic component and a second elastic component.
The paper feeder roller is equipped at one side of the paper case and connected with a transmission mechanism and a paper carrying roller. So the paper feeder roller rotates the same direction with the paper carrying roller. And the paper carrying roller can move downward to the paper case to have contact with the paper and move upward to lose contact with paper. So the paper carrying roller moves downward to carry it""s internal paper to move to the paper feeder roller along its rolling tangent direction.
This friction slice, with one side near the paper feeder roller and makes the paper locate between the friction slice and the paper feeder roller. Cause the friction coefficient between the material of the paper feeder roller and the paper is larger than that between the material of the friction slice and the paper and the friction coefficient between the material of the friction slice and the paper is larger than that between the paper and the paper, the paper feeder roller and the friction slice can separate the single page of paper.
The first elastic component is combined at the bottom of the friction slice to provide an elastic force perpendicular to the tangent direction and to make the friction slice approach the paper feeder roller.
The second elastic component is combined at the bottom of the friction slice to provide an elastic force contrary to the tangent direction and to make the friction slice move opposite the tangent direction.
These and other features and advantages of the present invention will be better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: